To shim or not to shim…

[BHP231]

1987 Euro spec car in Australia.
My boost gauge stopped working ages ago so I plumbed in a new after market one with a vacuum line above the KLR in to the new gauge on a bracket below the radio location.
In a moment of boredom today I pulled the dash out, gave it a clean up, pulled the boost needle off and put it back on and after putting back together the gauge works!

Question, dash boost gauge reads about 1.75 bar under load (I read that it is the correct stock level), aftermarket boost gauge reads 10psi at the same time. Obviously one is wrong… car pulls strongly under acceleration.
I was going to pull the wastegate and shim (as per Clark’s Garage), should I shim the wastegate or not? Thoughts and opinions?
Thanks

[kdjones2000]

Dash gauge reads absolute pressure, while aftermarket is reading atmospheric pressure.

Both sound about correct.

It's a race car? Does your boost drop off at high RPM? Shimming can help with that, or if ypu are running higher than stock boost levels.

[BHP231]

Thanks for the reply, I understand now.

It is a road car, stock boost, negligible drop off at high revs.

Will putting a shim or two in cause problems/damage or ok?

[nize]

our cars are getting old (mine has collector's plates!) so it's easy to "improve" one component and have it cause another aging component to fail. unless you're ready to go down the rabbit hole i would say if you're happy with the car, don't mess with it.

[soxnail]

I will second Nize, it gets to the point where one is scared just to look at the engine cross ways

[80sVibes]

Shim could help. It’s often recommended to replace the spring in the wastegate. There are apparently aftermarket springs with more tension. Makes more boost needed to bleed off.